Many cell therapies available for use today involve the use of specific tissue types, such as stem cells. These cells are used in a number of technologies but are particularly important in personalised or regenerative medicine. The use of these cells typically necessitates their isolation from a larger sample or organ, or part of an organ. Whilst, traditionally, tissue has been isolated using enzymatic digestion this can be slow, aggressive and indiscriminative. For example, it is known to use collagenase or other dissociating enzymes to breakdown the extracellular matrix, followed by centrifugation to separate the components of the extract. However calibrating the amount of collagenase so that just enough is used to disrupt the extracellular matrix whilst leaving the target tissue intact and fully functional is more of an art than a science and is influenced by the age of the tissue to be treated as well as its structural components and the relative amounts of those components. Moreover the task is further compounded by the fact that the activity of dissociating enzymes degrades over time and even from batch to batch and so each time an enzymatic digestion is performed a careful pre-calibration of the active enzyme needs to be undertaken. With all these variables, it is not surprising that the digestion results are often variable.
Cells can be isolated from a number of tissue types, for example Islets of Langerhans can be isolated form the pancreas, myocytes from the heart and stem cells from the bone marrow, oral mucosa and adipose tissue—to name just a few. However, it is necessary to ensure the isolated cell types retain their inherent functionality which, in the case of stem cells, is the ability to proliferate and give rise to multiple tissue types such as bone, cartilage, muscle, nerve, endocrine, epithelia and endothelia. Additionally, a source of stem cells or progenitor cells are also used for creating induced pluripotent stem cells.
It follows that if the isolation of cells is to be successful they must give rise to functional extracts and so a method of isolation that safeguards against cell damage is favoured. To this end, we report herein a form of mechanical extraction that favours the isolation of functional cell types and in particular stem or progenitor cells.